DESCRIPTION: (Applicant's Description) Palladium-catalyzed coupling reactions serve as extremely useful tools for the synthesis of biologically active compounds. We propose to develop more powerful catalysts for these reactions, focusing primarily on complexes that employ bulky, electron-rich P(t-Bu)3 as a ligand. For an array of important carbon-carbon bond-forming processes (e.g., Suzuki, Heck, Stille, and Negishi couplings), we intend to develop: general methods for coupling organic chlorides; versatile catalysts for coupling organic bromides, iodides, and triflates under mild conditions (e.g., at room temperature) and general methods for coupling organic phosphates and tosylates. Although our primary objective is to provide practical catalysts that will be widely applied by synthetic chemists both in basic research and in pharmaceutical/chemical development, we will also pursue mechanistic studies directed at furnishing an improved understanding of the origin of the unusual reactivity of Pd/P(t-Bu)3 in these coupling processes.